Investment Securities - Schedule of Contractual Maturities of Debt Securities (Details) $ in Millions	Dec. 31, 2021 USD ($)
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	$ 9,245
Available for sale, under 1 year, fair value	9,265
Available for sale, 1 to 5 years, amortized cost	38,447
Available for sale, 1 to 5 years, fair value	38,299
Available for sale, 6 to 10 years, amortized cost	13,827
Available for sale, 6 to 10 years, fair value	13,867
Available for sale, over 10 years, amortized cost	11,921
Available for sale, over 10 years, fair value	11,968
Available for sale, amortized cost	73,440
Available for sale, fair value	73,399
Held to maturity, under 1 year, amortized cost	3,071
Held to maturity, under 1 year, fair value	3,085
Held to maturity, 1 to 5 years, amortized cost	1,806
Held to maturity, 1 to 5 years, fair value	1,802
Held to maturity, 6 to 10 years, amortized cost	5,624
Held to maturity, 6 to 10 years, fair value	5,577
Held to maturity, over 10 years, amortized cost	31,929
Held to maturity, over 10 years, fair value	31,807
Held to maturity, amortized cost	42,430
Held to maturity, fair value	42,271
US Treasury and federal agencies, direct obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	1,977
Available for sale, under 1 year, fair value	1,976
Available for sale, 1 to 5 years, amortized cost	15,090
Available for sale, 1 to 5 years, fair value	14,912
Available for sale, 6 to 10 years, amortized cost	1,044
Available for sale, 6 to 10 years, fair value	1,051
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	18,111
Available for sale, fair value	17,939
Held to maturity, under 1 year, amortized cost	2,150
Held to maturity, under 1 year, fair value	2,159
Held to maturity, 1 to 5 years, amortized cost	3
Held to maturity, 1 to 5 years, fair value	3
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	16
Held to maturity, over 10 years, fair value	17
Held to maturity, amortized cost	2,170
Held to maturity, fair value	2,180
US Treasury and federal agencies, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	71
Available for sale, under 1 year, fair value	73
Available for sale, 1 to 5 years, amortized cost	839
Available for sale, 1 to 5 years, fair value	846
Available for sale, 6 to 10 years, amortized cost	7,619
Available for sale, 6 to 10 years, fair value	7,620
Available for sale, over 10 years, amortized cost	9,625
Available for sale, over 10 years, fair value	9,669
Available for sale, amortized cost	18,154
Available for sale, fair value	18,208
Held to maturity, under 1 year, amortized cost	148
Held to maturity, under 1 year, fair value	151
Held to maturity, 1 to 5 years, amortized cost	393
Held to maturity, 1 to 5 years, fair value	399
Held to maturity, 6 to 10 years, amortized cost	4,651
Held to maturity, 6 to 10 years, fair value	4,591
Held to maturity, over 10 years, amortized cost	28,289
Held to maturity, over 10 years, fair value	28,124
Held to maturity, amortized cost	33,481
Held to maturity, fair value	33,265
Total U.S. Treasury and federal agencies
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	2,048
Available for sale, under 1 year, fair value	2,049
Available for sale, 1 to 5 years, amortized cost	15,929
Available for sale, 1 to 5 years, fair value	15,758
Available for sale, 6 to 10 years, amortized cost	8,663
Available for sale, 6 to 10 years, fair value	8,671
Available for sale, over 10 years, amortized cost	9,625
Available for sale, over 10 years, fair value	9,669
Available for sale, amortized cost	36,265
Available for sale, fair value	36,147
Held to maturity, under 1 year, amortized cost	2,298
Held to maturity, under 1 year, fair value	2,310
Held to maturity, 1 to 5 years, amortized cost	396
Held to maturity, 1 to 5 years, fair value	402
Held to maturity, 6 to 10 years, amortized cost	4,652
Held to maturity, 6 to 10 years, fair value	4,592
Held to maturity, over 10 years, amortized cost	28,305
Held to maturity, over 10 years, fair value	28,141
Held to maturity, amortized cost	35,651
Held to maturity, fair value	35,445
Non-U.S. debt securities, mortgage-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	164
Available for sale, under 1 year, fair value	164
Available for sale, 1 to 5 years, amortized cost	526
Available for sale, 1 to 5 years, fair value	527
Available for sale, 6 to 10 years, amortized cost	33
Available for sale, 6 to 10 years, fair value	33
Available for sale, over 10 years, amortized cost	1,263
Available for sale, over 10 years, fair value	1,271
Available for sale, amortized cost	1,986
Available for sale, fair value	1,995
Non-U.S. debt securities, asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	303
Available for sale, under 1 year, fair value	302
Available for sale, 1 to 5 years, amortized cost	1,040
Available for sale, 1 to 5 years, fair value	1,041
Available for sale, 6 to 10 years, amortized cost	454
Available for sale, 6 to 10 years, fair value	454
Available for sale, over 10 years, amortized cost	290
Available for sale, over 10 years, fair value	290
Available for sale, amortized cost	2,087
Available for sale, fair value	2,087
Non-U.S. sovereign, supranational and non-U.S. agency
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	4,472
Available for sale, under 1 year, fair value	4,480
Available for sale, 1 to 5 years, amortized cost	16,329
Available for sale, 1 to 5 years, fair value	16,336
Available for sale, 6 to 10 years, amortized cost	2,717
Available for sale, 6 to 10 years, fair value	2,717
Available for sale, over 10 years, amortized cost	15
Available for sale, over 10 years, fair value	14
Available for sale, amortized cost	23,533
Available for sale, fair value	23,547
Held to maturity, under 1 year, amortized cost	345
Held to maturity, under 1 year, fair value	345
Held to maturity, 1 to 5 years, amortized cost	1,218
Held to maturity, 1 to 5 years, fair value	1,209
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	0
Held to maturity, over 10 years, fair value	0
Held to maturity, amortized cost	1,564
Held to maturity, fair value	1,555
Non-U.S. debt securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	823
Available for sale, under 1 year, fair value	826
Available for sale, 1 to 5 years, amortized cost	1,954
Available for sale, 1 to 5 years, fair value	1,943
Available for sale, 6 to 10 years, amortized cost	279
Available for sale, 6 to 10 years, fair value	275
Available for sale, over 10 years, amortized cost	57
Available for sale, over 10 years, fair value	54
Available for sale, amortized cost	3,113
Available for sale, fair value	3,098
Total non-U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	5,762
Available for sale, under 1 year, fair value	5,772
Available for sale, 1 to 5 years, amortized cost	19,849
Available for sale, 1 to 5 years, fair value	19,847
Available for sale, 6 to 10 years, amortized cost	3,483
Available for sale, 6 to 10 years, fair value	3,479
Available for sale, over 10 years, amortized cost	1,625
Available for sale, over 10 years, fair value	1,629
Available for sale, amortized cost	30,719
Available for sale, fair value	30,727
Held to maturity, under 1 year, amortized cost	345
Held to maturity, under 1 year, fair value	345
Held to maturity, 1 to 5 years, amortized cost	1,218
Held to maturity, 1 to 5 years, fair value	1,209
Held to maturity, 6 to 10 years, amortized cost	1
Held to maturity, 6 to 10 years, fair value	1
Held to maturity, over 10 years, amortized cost	0
Held to maturity, over 10 years, fair value	0
Held to maturity, amortized cost	1,564
Held to maturity, fair value	1,555
Asset-backed securities, student loans
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	113
Available for sale, under 1 year, fair value	115
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	0
Available for sale, 6 to 10 years, fair value	0
Available for sale, over 10 years, amortized cost	96
Available for sale, over 10 years, fair value	96
Available for sale, amortized cost	209
Available for sale, fair value	211
Held to maturity, under 1 year, amortized cost	341
Held to maturity, under 1 year, fair value	335
Held to maturity, 1 to 5 years, amortized cost	48
Held to maturity, 1 to 5 years, fair value	47
Held to maturity, 6 to 10 years, amortized cost	971
Held to maturity, 6 to 10 years, fair value	984
Held to maturity, over 10 years, amortized cost	3,548
Held to maturity, over 10 years, fair value	3,576
Held to maturity, amortized cost	4,908
Held to maturity, fair value	4,942
Asset-backed securities, collateralized loan obligations
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	147
Available for sale, under 1 year, fair value	147
Available for sale, 1 to 5 years, amortized cost	482
Available for sale, 1 to 5 years, fair value	483
Available for sale, 6 to 10 years, amortized cost	1,085
Available for sale, 6 to 10 years, fair value	1,084
Available for sale, over 10 years, amortized cost	441
Available for sale, over 10 years, fair value	441
Available for sale, amortized cost	2,155
Available for sale, fair value	2,155
Asset-backed securities, non-agency CMBS and RMBS
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	0
Available for sale, under 1 year, fair value	0
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	0
Available for sale, 6 to 10 years, fair value	0
Available for sale, over 10 years, amortized cost	52
Available for sale, over 10 years, fair value	52
Available for sale, amortized cost	52
Available for sale, fair value	52
Held to maturity, under 1 year, amortized cost	87
Held to maturity, under 1 year, fair value	95
Held to maturity, 1 to 5 years, amortized cost	144
Held to maturity, 1 to 5 years, fair value	144
Held to maturity, 6 to 10 years, amortized cost	0
Held to maturity, 6 to 10 years, fair value	0
Held to maturity, over 10 years, amortized cost	76
Held to maturity, over 10 years, fair value	90
Held to maturity, amortized cost	307
Held to maturity, fair value	329
Asset-backed securities, other
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	0
Available for sale, under 1 year, fair value	0
Available for sale, 1 to 5 years, amortized cost	0
Available for sale, 1 to 5 years, fair value	0
Available for sale, 6 to 10 years, amortized cost	90
Available for sale, 6 to 10 years, fair value	91
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	90
Available for sale, fair value	91
Total asset-backed securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	260
Available for sale, under 1 year, fair value	262
Available for sale, 1 to 5 years, amortized cost	482
Available for sale, 1 to 5 years, fair value	483
Available for sale, 6 to 10 years, amortized cost	1,175
Available for sale, 6 to 10 years, fair value	1,175
Available for sale, over 10 years, amortized cost	589
Available for sale, over 10 years, fair value	589
Available for sale, amortized cost	2,506
Available for sale, fair value	2,509
Held to maturity, under 1 year, amortized cost	428
Held to maturity, under 1 year, fair value	430
Held to maturity, 1 to 5 years, amortized cost	192
Held to maturity, 1 to 5 years, fair value	191
Held to maturity, 6 to 10 years, amortized cost	971
Held to maturity, 6 to 10 years, fair value	984
Held to maturity, over 10 years, amortized cost	3,624
Held to maturity, over 10 years, fair value	3,666
Held to maturity, amortized cost	5,215
Held to maturity, fair value	5,271
State and political subdivisions
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	177
Available for sale, under 1 year, fair value	180
Available for sale, 1 to 5 years, amortized cost	491
Available for sale, 1 to 5 years, fair value	512
Available for sale, 6 to 10 years, amortized cost	466
Available for sale, 6 to 10 years, fair value	499
Available for sale, over 10 years, amortized cost	82
Available for sale, over 10 years, fair value	81
Available for sale, amortized cost	1,216
Available for sale, fair value	1,272
Other U.S. debt securities
Contractual Maturities Of Debt Investment Securities [Line Items]
Available for sale, under 1 year, amortized cost	998
Available for sale, under 1 year, fair value	1,002
Available for sale, 1 to 5 years, amortized cost	1,696
Available for sale, 1 to 5 years, fair value	1,699
Available for sale, 6 to 10 years, amortized cost	40
Available for sale, 6 to 10 years, fair value	43
Available for sale, over 10 years, amortized cost	0
Available for sale, over 10 years, fair value	0
Available for sale, amortized cost	2,734
Available for sale, fair value	$ 2,744